Is there any information on how long it takes HIV to have serious effects on the brain? A friend who is a longtimer (18 years) has been diagnosed with AIDS Related Dementia and this has caused me to wonder how HIV attacks the brain, What it does, how long are AZT, 3TC and other drugs that break the blood/brain barrier effective in fighting ADC?

Hope that's not too much for 1 question. I myself have had HIV for a little over 2 years so while not seriously worried I am concerned about what I can do to prevent this from happening in my life.

HIV infects cells in the brain, and usually people who have been + for a long time are the ones that develop ADC (AIDS dementia complex). This seems to be less common as more powerful drugs for HIV have become available. I can't give you a timeline for when this happens or for how long the drugs are effective. In general, if your viral load is low or undetectable and you have had a good CD4 cell response to combination therapy for HIV, the chances of developing ADC are much diminished, but are probably not zero.